神秘的编译器错误，可能与使用“虚拟”有关

我收到这个编译器错误。我有几百行代码，所以我会发布一些我认为可能相关的代码，但你需要告诉我你想看到什么。

这是我在编译时收到的错误：

/tmp/ccBE5kZ5.o:game.cpp:(.text+0x1067): undefined reference to `vtable for Person'
/tmp/ccBE5kZ5.o:game.cpp:(.text+0x17a5): undefined reference to `vtable for Person'
/tmp/ccBE5kZ5.o:game.cpp:(.text+0x1ee6): undefined reference to `vtable for Person'
/tmp/ccBE5kZ5.o:game.cpp:(.text+0x2560): undefined reference to `vtable for Person'
/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../../i686-pc-cygwin/bin/ld: /tmp/ccBE5kZ5.o: bad reloc address 0xc in section `.text$_ZN6WeaponD1Ev[Weapon::~Weapon()]'
/usr/lib/gcc/i686-pc-cygwin/3.4.4/../../../../i686-pc-cygwin/bin/ld: final link failed: Invalid operation
collect2: ld returned 1 exit status

以下是我的Person类和Weapon类的声明，以及Person所属的Actor类：

class Actor {
public:
virtual void act();
virtual string getName();
virtual void setName(string n);
Actor();
Actor(string n);
virtual ~Actor();
private:
string name;
};

class Person : public Actor {
public:
void act();
virtual void fight(Person enemy);
virtual void takeDamage(double dmg);
// getters and setters
virtual unsigned getX();
virtual void setX(unsigned amt);
virtual unsigned getY();
virtual void setY(unsigned amt);
virtual Weapon getWeapon();
virtual void setWeapon(Weapon w);
virtual Weapon getArmor();
virtual void setArmor(Weapon a);
virtual unsigned getLevel();
virtual void setLevel(unsigned amt);
virtual double getHealth();
virtual void setHealth(double amt);
virtual double getXP();
virtual void setXP(double amt);
Person();
Person(string n);
private:
Weapon wep;
Weapon armor;
double xp;
unsigned level;
double health;
unsigned x;
unsigned y;
};

class Weapon {
public:
double getStrength();
void setStrength(double s);
double getValue();
void setValue(double amt);
double getHealth();
void setHealth(double amt);
string getName();
void setName(string n);
string getType();
void setType(string t);
Weapon();
Weapon(string n, string t, double dmg);
private:
string name;
string type;
double value;
double health;
double strength;
};